A phase I study of intravenous (IV) milataxel in combination with carboplatin in adult patients with advanced malignant solid tumors
e13525 Background: Milataxel (MXL) is a novel taxane with activity in human xenograft models against tumors resistant to paclitaxel. The primary objective of this study was to determine the MTD when MXL was given intravenously in combination with a fixed dose (AUC=6) of carboplatin (C) every 21 days in subjects with advanced malignant solid tumors. Secondary objectives were to (i) assess the safety and tolerability of the combination (ii) define the pharmacokinetics of MXL and C when given in combination (iii) obtain preliminary information on the antitumor activity of MXL+C. Methods: Key subject eligibility criteria included: adult pts with refractory malignant tumors, ECOG PS <3 and adequate hematologic, hepatic and renal function. PK data was obtained on day 1 for MXL and both free and bound platinum. Results: 11 pts (median age 60; 2 F,9 M) were treated. MXL was dose escalated in three cohorts (15, 20 and 25 mg/m2). Three patients were treated at 15 mg/m2 of MXL without a DLT. At the 25 mg/m2 dose of MXL there were two DLT's out of the 4 pts enrolled at this dose (1 pt - grade 3 febrile neutropenia, grade 4 thrombocytopenia; 1 pt - grade 4 ANC, grade 4 thrombocytopenia). At the 20 mg/m2 dose of MXL there were two DLT's out of the 4 pts enrolled at this dose with both pts having grade 4 ANC. The MTD and the recommended Phase II dose of MXL was 15 mg/m2 plus C (AUC= 6). The median number of cycles administered was 3 (range 1–16). The most frequent grade 3 or 4 treatment emergent adverse events were neutropenia (82%), leukopenia (55%), pancytopenia (27%), asthenia (18%), generalized edema (18%), thrombocytopenia (18%), anemia (18%), confusion (18%), and dyspnea (18%). One pt in the MTD cohort with cholangiocarcinoma had a PR. This patient received 16 cycles of therapy and had a response duration of 378 days and a TTP of 406 days. PK data (n=9) showed the elimination half-life of MXL ranged from 26 to 110 h, and that for free and total platinum were as would be predicted for C monotherapy. Conclusions: The MTD of MXL was 15 mg/m2 IV per three week cycle when combined with carboplatin (AUC= 6). One patient with a cholangiocarcinoma had a sustained PR for 378 days. No significant financial relationships to disclose.